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Biology
IB

Explain how blood is pumped through the body.

Blood from the veins is collected in the right and left atria of the heart. The atria can contract because of the impulses from the sinoatrial node (SA) (the heart’s natural pacemaker). When this happens,...

Answered by Iulia B. Biology tutor
1662 Views

Membranes of pre-synaptic and post-synaptic neurons play an important role in transmission of nerve impulses. Explain the principles of synaptic transmission. (8marks)

Synapse is the gap between two adjacent neurons in which neurotransmitters are released. Arriving action potential depolarises pre-synaptic membrane. This causes voltage gated calcium channels in membrane...

Answered by Alla K. Biology tutor
2230 Views

Draw the structure of a cell membrane (6 marks).

I would draw a diagram showing the structure of a cell membrane and explain each of the parts:The cell membrane is composed of a phospholipid bilayer which is composed of a hydrophilic head and a hydropho...

Answered by Pravir M. Biology tutor
1916 Views

Describe the cardiac cycle in the human heart

The human heart beats around 60-100 beats per minute. Blood enters the right atrium via the superior vena cava and the inferior vena cava, the blood moves through the tricuspid valve into the right ventri...

Answered by Shane D. Biology tutor
1760 Views

How does an electrical impulse travel from one neuron to the next (IB-SL 6.5)?

  1. The arrival of an action potential at the synaptic knob opens calcium ion channels in the pre-synaptic membrane and Ca++ flow in from the synaptic cleft 2. Ca++ cause vesicles of neurotransmitters t...
Answered by Adam K. Biology tutor
1636 Views

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